Invariant Definitions

This lecture covers the definition of invariants in the context of sets, focusing on groups and automorphisms. It explains the concept of invariance in various settings and provides examples of p-divisible groups with elements of p-torsion. The lecture also delves into the theory of free abelian groups and the Yoneda lemma, showcasing the properties of universal properties and functors. Additionally, it explores the notion of free objects and their applications, as well as the categorical interpretation of power sets and inclusion mappings.